Burner devices and combustion chambers therefor



Jan. 3, 1967 1 J. BAUGER ETAL 3,295,318

BURNER DEVICES AND COMBUSTION CHAMBERS THEREFOR Filed June '7, 1965 5Sheets-Sheet 1 BURNER DEVICES AND coMBUsTloN CHAMBERS THEEEFOR FiledJune '7, 1955 Jan. 3, 1967 J. BAUGER ETAL I5 Sheets-Sheet 2 ATT c kwel 5BURNER DEVICESV AND COMBUSTION CHAMBERS THEREFOR Filed June '7. 1965Jan. 3, 1967 L. J. BAUGER ETAL 5 Sheets-$heet 5 Iman-vues Louis Jues347er', t rJ 16:14/ @mbe ferrnnuanJ Jean-Bqf'sfz. Acto Piano. Jean VidarNegra 3)/ mmm'LE, Q/ennwx MJ WATSON United States Patent O 3,295,318BURNER DEVICES AND COMBUSTION CHAMBERS THEREFOR Louis Jules Bauger,Vanves, Bernard Pani Emile Gambet, Dammarie-les-Lys, Armand `ieanBaptiste Lacroix, Itteville, and Pierre liean Victor Negro, Paris,France, assignors to Societe Nationale dEtude et de Construction deMoteurs dAviation, Paris France, a company of France Filed .lune 7,1965, Ser. No. 462,015 Claims priority, application France, June 9,1964,

4 Claims. (Cl. oil-39.72)

The combustion chambers of aeronautical turbo-engines are subject tohigh thermal loads and, so as not to require too large over-alldimensions, it is necessary to make the fullest possible use of thecross-section of the combustion chamber for the installation ofilameholders, while avoiding excessive loss of static pressure.

However, the use of a plurality of ameholders and fuel supply manifoldsor racks makes other combustion problems particularly acute, theseproblems including the need for ensuring uniform distribution oftemperature at the outlet from the combustion chamber, correctatomization of the fuel and easy propagation of the flame on ignition.

It is an object of the present invention to provide a burner devicewhich will offer a satisfactory solution to such problems. The deviceprovided by the invention of the type comprising two or more concentricrings of V-shaped radial cross-section which are open in the downstreamdirection and perform the function of ame stabilizers, the means formounting these rings in a oombustion chamber being devised so as not todisturb ap preciably, the flow in the combustion chamber.

According to the present invention, the rings are linked by a rigidinterconnection system constituted by a series of profiled hollow radialarms or struts which are distributed transversely in the combustionchamber and each of which opens at its opposite ends into the internalspace of the respective rings, the assembly comprising the rings and thehollow radial arms or struts forming a rigid unitary assembly.

According to a preferred embodiment of the invention, one or more fuelinjectors are housed inside each hollow proled strut, air inlet orificesbeing formed in the leading or upstream edges of the respective strutsin the proximity of the said injectors. Thus, air and fuel can enter theflame-holder rings by way of the hollow struts, together with, in thecase where one -or more of the struts Contains a sparking plug or otherignition device, an ignition ame. Openings may also be formed in thetrailing edges of the hollow profiled struts for the discharge ofcarburetted mixture directly into the combustion charnber. In this casea screen, in the form of an annular plate for example, is advantageouslydisposed opposite the said outlet openings, in the path of the air-fuelmixture which is generated thereby.

The following description with reference to the acc-om panying drawings,of one form of burner device according to the invention, which is givenby way of nonlimitative example only, will make it clearly understoodhow the invention can be carried into effect. In the drawings:

FIGURE l is a fragmentary diagrammatical view of the burner device;

FIGURE 2 is a fragmentary sectional view through the upstream portion ofa combustion chamber in which the burner device is arranged, the burnerdevice being shown in radial section on the line II-II of FIGURE l;

FIGURE 3 is a radial section on the line III- III of FIGURE 1;

3,295,318 Patented Jan. 3, 1967 ICC FIGURES 4 and 5 are fragmentarysections on the line IV-IV of FIGURE 3 and the line V-V of FIG- URE 2,respectively.

Referring to the drawings, the burner device is mounted in thecombustion chamber 1 of a jet propulsion unit, the combustion chamberbeing dened by two annular sleeves 2;, 3. The burner device isconstituted primarily by two concentric and ooplanar rings 4, 5 ofgenerally Vshaped cross-section, arranged with their open sides in thedownstream direction, and by a fuel manifold 6 extending around thecircumference of a circle whose radius is intermediate between the radiiof the rings 4 and 5 and concentric with the latter.

The two burner rings 4 and 5 are connected by a number of tubular radialinterconnecting arms or struts 7 distributed around the combustionchamber ll and profiled so as to reduce the drag which they present tothe ow of air passing through the chamber (the aerodynamic profile ofthe struts 7 can be clearly seen in FIG- URE 4. The struts 7 are tubularor hollow and are seccured in radial positions by welding them to theopposed `faces of the V-shaped rings 4 and 5. The walls of the faces areapertured at 4a and 5a at the places where they are intersected by thetubular struts 7, so that the latter communicate with the interior ofthe rings at each end.

The manifold 6 which is disposed upstream of the struts 7 carriesinjection nozzles or heads 8 which are welded thereto and which extendinto the interior of the struts 7 through orifices 9 formed for thispurpose (see FIGURES 3 and 4). The diameter of the said orifices 9 issufficient to permit a flow of air around the injectors 8 so as toobtain a suitable mixture of air and fuel. Further orifices 10 areformed in the struts 7, at the downstream sides thereof, so as to allowthe carburetted mixture to pass out. A narrow annular plate 11 is arranged coaxially between and somewhat downstream of the burner rings 4and 5, at equal radial distances from them; the plate 11 is held byspacers 12 fixed to the downstream sides of the respective struts 7.

This arrangement enables the fuel to be injected under high pressure, byreason of the smaller number of injection holes which are provided. Thefuel is atomized when the jet of fuel issuing from each injector 8 comesinto contact with the downstream part of the associated hollow strut 7and further, when the fuel passes out through the hole 10 and strikesagainst the annular plate 11 which acts as a screen. It is sprayedfinely into the surrounding air and the mixture is distributed in thetwo wakes formed by the burner rings 4 and 5, where it can burn. Inorder to prevent the mixture being carried away between the two wakeswithout burning therein, the sides of the two rings which face oneanother are preferably inclined to a greater extent with respect to thegeneral axis of the chamber than the sides which are remote from oneanother (as can be seen in the drawings), so as to bring the wakescloser to the median space.

As a variant, instead of each injector 8 producing one or more jetsdirected towards the annular plate 11 in the same general direction asthe direction of the flow of air, it can emit jets which are obliquewith respect to the air flow, being directed towards the openings 4a, 5aby way of which the corresponding strut 7 communicates with the internalspace of the rings 4 and 5. Atomization of the fuel will then take placeon the outer lips of the rings 4 and 5 instead of occurring on theannular place 11 as before. Moreover, the two methods of injection maybe employed simultaneously.

It will be quite obvious that air can be supplied to the interior of thestruts 7 at a pressure higher than the normal pressure of entry into thecombustion chamber,

simply by connecting the orifices 9 to a source of air which is subjectto overpressure. Similarly, a supply of hot air can be provided bytaking the air from, for example, the turbine of the jet engine.

The arrangement for suspending the two rings 4 and 5 and the fuelmanifold 6 from the outer sleeve 2 of the combustion chamber will now bedescribed, with particular reference to FIGURES 2 and 5.

The arrangement comprises a set of linking bars 13 which are pivotallyconnected at their ends, by means of axes 14 and 15 and securing pins16, to T-section supports 17 and 18 which are welded to the rings 4 and5 the leading edge shape of which they take. Each linking bar 13 is alsoarticulated at its centre by means of an axis 19, likewise provided withsecuring pins 16, to a support 20 fast with the fuel manifold 6. To thissame axis 19 there is coupled one end of a connecting rod 21 which ispivotally connected at its other end to the outer sleeve 2, at 22, thepivot pin 22 being mounted in a fork 23 which has a threaded boss 24integral therewith, the threaded part of which extends through a holeformed in the sleeve 2 and receiving a self-locking nut 25. Of course,the suspension arrangement comprises a number of articulated connectingrods 21 distributed around the cross-section of the combustion chamberso as to support the burner device as a Whole at the correct position.

It will be observed, however, that it is the struts 7 welded to therings 4 and 5 which determine the positions of the latter relatively toone another and not the linkage bars 13 and 21, which support the burnerdevice as a whole. The mounting of the burner device in the combustionchamber 1 therefore cannot introduce any additional stress due toexpansion movements of the rings 4 and relatively to one another.

The device which has just been described has many advantages, amongwhich the following may be mentioned.

(1) More uniform radial distribution of temperature. The minimumtemperature occurring between the two maximum temperature positionscorresponding to the two rings 4 and 5 is increased due to the presenceof the struts 7 and the plate 11. The result is greater eiiiciency,improved stability of combustion and, in the case where there is aturbine at the outlet of the chamber, better behaviour of the blades ofthe turbine for a given temperature.

(2) Elimination of coking of the fuel before injection. This is achievedbecause the manifold 6 is well upstream of the llame-front of the burnerrings 4 and 5 and because the injection nozzles 8 are protected fromradiation by the struts 7.

(3) Improvement of the propagation of ignition. This is achieved becausethe struts 7, which propagate the flame from one burner to the other,shelter the flame from the air flowing through the combustion chamber.Only a single sparking plug, such as indicated at 26 in FIGURE 2, isrequired to cause ignition at both the rings 4 and 5.

It will be obvious that many modifications may be made in the particularembodiment which has just been described, in particular by substitutingequivalent technical means, without thereby departing from the scope ofthe invention as defined by the appended claims.

What we claim is:

1. An improvement in combustion equipments for combustion chambersdesigned to be traversed by a highvelocity air flow and of the kindcomprising at least two annular flame-holder rings of V-shaped radialcross-section defining an inner space closed upstream at the apex ofsaid V cross-section and open downstream, said rings being of differentradii and arranged concentrically of each other, and a plurality ofgenerally radial hollow struts extending between said concentric ringsand cornmunicating with said inner space thereof, said concentric ringsand said radial struts forming a rigid unitary assembly, wherein saidimprovement comprises an annular fuel manifold having a radiusintermediate the radii of said rings and arranged coaxially with respectthereto and upstream of said assembly, an inlet passage formed in theleading edge of said hollow struts at substantially the same radialdistance as the radius of said fuel manifold, said inlet passage facingupstream toward said fuel manifold, and a fuel jet nozzle projectingfrom said manifold and through said inlet passage into the respectivehollow radial strut, a substantial clearance being left between theperiphery of said inlet passage and said fuel jet nozzle to allow inflowof air into said strut around said nozzle.

2. A combustion equipment as claimed in claim 1, comprising further anignition means housed in at least one of said hollow struts, forigniting the mixture formed therein of fuel discharged by said fuel jetnozzle and of air admitted through said inlet passage.

3. A combustion equipment as claimed in claim 1, comprising further anoutlet passage formed in the trailing edge of said hollow struts andfacing downstream, and deecting means positioned downstream of saidstruts and opposite the outlet passage thereof, to deflect uid issuingfrom said outlet passage radially outward and inward toward the innerspace of the flame-holder rings.

4. A combustion equipment as claimed in claim 3, wherein said deectingmeans comprises an annular plate having substantially the same radius asthe radial distance of said outlet passage.

References Cited bythe Examiner UNITED STATES PATENTS 3,046,731 7/1962Cambel 60-39.72 3,196,614 7/1965 Toone 60-39.72 X MARK NEWMAN, PrimaryExaner.

RALPH D. BLAKESLEE, Examiner.

1. AN IMPROVEMENT IN COMBUSTION EQUIPMENTS FOR COMBUSTION CHAMBERSDESIGNED TO BE TRANSVERSED BY A HIGHVELOCITY AIR FLOW AND OF THE KINDCOMPRISING AT LEAST TWO ANNULAR FLAME-HOLDER RINGS OF V-SHAPED RADIALCROSS-SECTION DEFINING AN INNER SPACE CLOSED UPSTREAM AT THE APEX OFSAID V CROSS-SECTION AND OPEN DOWNSTREAM, SAID RINGS BEING OF DIFFERENTRADII AND ARRANGED CONCENTRICALLY OF EACH OTHER, AND A PLURALITY OFGENERALLY RADIAL HOLLOW SRUTS EXTENDING BETWEEN SAID CONCENTRIC RINGSAND COMMUNICATING WITH SAID INNER SPACE THEREOF, SAID CONCENTRIC RINGSAND SAID RADIAL STRUTS FORMING A RIGID UNITARY ASSEMBLY, WHEREIN SAIDIMPROVEMENT COMPRISES AN ANNULAR FUEL MANIFOLD HAVING A RADIUSINTERMEDIATE THE RADII OF SAID